1. Field of the Invention
The present invention relates to digital devices. More specifically, the present invention relates to a copy management system and method for controlling the reproduction and recording of digital content on and from at least one digital device.
2. General Background
Analog communication systems are rapidly giving way to their digital counterparts. Digital television is currently scheduled to be available nationally to all consumers by the year 2002 and completely in place by the year 2006. High-definition television (HDTV) broadcasts have already begun in most major cities on a limited basis. Similarly, the explosive growth of the Internet and the World Wide Web have resulted in a correlative growth in the increase of downloadable audio-visual files, such as MP3-formatted audio files, as well as other content.
Simultaneously with, and in part due to, this rapid move to digital communications system, there have been significant advances in digital recording devices. Digital versatile disk (DVD) recorders, digital VHS video cassette recorders (D-VHS VCR), CD-ROM recorders (e.g., CD-R and CD-RW), MP3 recording devices, and hard disk-based recording units are but merely representative of the digital recording devices that are capable of producing high quality recordings and copies thereof, without the generational degradation (i.e., increased degradation between successive copies) known in the analog counterparts. The combination of movement towards digital communication systems and digital recording devices poses a concern to content providers such as the motion picture and music industries, who desire to prevent the unauthorized and uncontrolled copying of copyrighted, or otherwise protected, material.
In response, there is a movement to require service providers, such as terrestrial broadcast, cable and direct broadcast satellite (DBS) companies, and companies having Internet sites which provide downloadable content, to introduce protection schemes. Two such copy protection systems have been proposed by the 5C group of the Data Hiding Sub Group (DHSG) (5C comprising representatives of Sony, Hitachi, Toshiba, Matsushita, and Intel) and the Data Transmission Discussion Group (DTDG), which are industry committee sub-groups of the Copy Protection Technical Working Group (CPTWG). The CPTWG represents the content providers, computer and consumer electronic product manufacturers.
The DTDG Digital Transmission Copy Protection (DTCP) proposal is targeted for protecting copy-protected digital content, which is transferred between digital devices connected via a digital transmission medium such as an IEEE 1394 serial bus. Device-based, the proposal uses symmetric key cryptographic techniques to encode components of a compliant device. This allows for the authentication of any digital device prior to the transmission of the digital content in order to determine whether the device is compliant. The digital content is itself encoded prior to transmission so that unauthorized copying of the content will result in copy having an unintelligible format.
Thus, even today, the functionality of digital devices such as set-top boxes, digital televisions, digital audio players, and similar such digital devices extends beyond their historical role of conditional access (CA), i.e., merely descrambling content to a CA-clear format for real-time viewing and/or listening, and now include constraints and conditions on the recording and playback of such digital content. For example, currently, copying of scrambled content for subsequent descrambling and viewing or listening may be permitted with the appropriate service/content provider authorization or key provided to the digital device.